Observations on Pearls Reportedly from the Pinnidae Family (Pen Pearls)
Examines the internal structure, chemical composition, and spectroscopic features of 22 pen pearls.
Characterization of “Green Amber” With Infrared and Nuclear Magnetic Resonance Spectroscopy
A peridot-like bright greenish yellow to green gem material called “green amber” has recently appeared in the gem market.
A Comparison of Modern and Fossil Ivories Using Multiple Techniques
This article provides identification criteria to distinguish between modern and fossil (mammoth) elephant ivory.
Identification of the Endangered Pink-To-Red Stylaster Corals by Raman Spectroscopy
All corals within the Stylasteridae family (including the Stylaster genus) are listed in Appendix II of CITES.
The author reviews the nature of this material and some of the forms into which it has been fashioned, as well as means of identifying hornbill ivory from other ivories and from imitations.
A Look Inside a Remarkably Large Beaded South Sea Cultured Pearl
A study of the nacre and the cavity of a large Pinctada maxima cultured pearl yields a theory on the specimen’s formation.